Installation tool for suture anchor

ABSTRACT

A tool for installing a suture anchor which supports first and second suture segments having free ends, the tool including an installation end adapted to accommodate the suture anchor and to transmit mechanical power for driving the suture anchor, and a guiding arrangement adapted to guide and support the first and second suture segments in a non-parallel configuration at the installation end. The guiding arrangement may include at least one suture guide adapted to support the first and second suture segments, respectively, at least at a first and a second support points, which are spaced laterally with respect to a direction of installation of the suture anchor.

FIELD OF THE INVENTION

The present invention relates generally to installation of sutureanchors and, more particularly, to a tool for installing suture anchors.

BACKGROUND OF THE INVENTION

Suture anchors are widely used in surgery, particularly for attachingsutures to bones in orthopedic surgical procedures. The suture anchorconnects a portion of a suture to a bone, while the remainder of thesuture (typically, two segments extending from the suture anchor) isused for various applications, e.g., for securing loosened connectivetissue, such as ligament, to the bone. The suture anchor is typicallydriven into a hole made in the bone, e.g., into a pre-drilled hole.Suture anchors are particularly useful for firmly attaching sutures tobones during and after orthopedic surgery.

Suture anchors and tools for installing suture anchors are described inU.S. Pat. Nos. 5,207,679, 5,411,523 and 5,217,486, and in PCTpublication WO 96/28100.

U.S. Pat. No. 5,411,523 describes a suture anchor and installation toolcombination. The suture is threaded through a ring attached to aremovable link member which is connected to an installation end of theinstallation tool. The threaded suture is folded into two free-endedsegments which are guided together through a single bore formed in theinstallation tool. By applying a driving force to the installation tool,the suture anchor is driven into a pre-drilled hole in the bone togetherwith a portion of the suture.

PCT publication WO 96/28100 also describes a suture anchor installationtool, wherein the suture is attached to the suture anchor and twofree-ended segments of the suture are guided together through theinstallation tool. The suture anchor is driven into the bone by a forcewhich is transmitted thereto by the installation tool.

Likewise, both U.S. Pat. Nos. 5,207,679 and 5,217,486 describe aninstallation tool for a suture anchor. In the devices described in thesepatents, the suture is threaded through a loop which is attached to thesuture anchor and the installation tool drives the suture anchor into apre-drilled hole, but the free ended segments of the suture are notguided through the installation tool.

Each of the prior art devices described above is susceptible to theeffect of lateral forces which may act on the suture anchor and/or onthe installation tool during installation. In response to such lateralforces, the installation tool may skew with respect to the suture anchorand/or the suture anchor may skew in the pre-drilled hole. Consequently,the suture anchor and/or the installation tool may be damaged and thesuture anchor may be improperly installed in the bone.

Further, in prior art devices, a certain degree of freedom between thesuture anchor and the installation tool may result in lateral movementof the suture anchor upon installation. Such lateral movement makes itdifficult to align the suture anchor with respect to the pre-drilledhole. Thus, installation of a suture anchor is generally difficult andrequires very high precision. Additionally, there is often insufficientspace for maneuvering the installation tool at the installation site tocompensate for lateral movement of the suture anchor.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to overcome thedrawbacks of prior art tools for installing suture anchors. Morespecifically, the present invention provides a suture anchorinstallation tool which makes the installation of suture anchors simplerand more reliable, reducing the risk of damaging the suture anchors orthe installation tool.

In the present invention, a suture anchor supporting first and secondsuture segments is mounted on an installation end of an installationtool. The installation end includes an arrangement for transmittingmechanical power to the suture anchor to drive the suture anchor into abone. The installation tool further includes a guiding arrangement whichguides and supports the first and second suture segments near theinstallation end in a non-parallel configuration, wherein the distancebetween the first and second suture segments changes near theinstallation end. For example, in some embodiments of the invention, thepaths of the first and second suture segments are crossed near theinstallation end.

The non-parallel configuration of the suture segments near theinstallation end of the present invention enables, inter alia,compensation for lateral forces which may act on the suture anchorand/or the installation end during installation. When the suturesegments are tensioned, e.g., by pulling their free ends, the forcesapplied to the installation end by the first and second suture segmentshave opposite lateral components. However, the longitudinal componentsof the forces applied by the first and second suture segments are bothoperative to pull the suture anchor against the installation end. Thus,by controlling the relative tensions of the suture segments in thepresent invention, it is possible to counteract lateral forces acting onthe suture anchor and/or the installation end, while maintaining thesuture anchor securely mounted on the installation end. For example,when a lateral force tilts the suture anchor in the direction of thefirst suture segment, the tension in the second suture segment isincreased relative to the first suture segment and, thus, the sutureanchor is urged back to its original position. Similarly, when a lateralforce tilts the suture anchor in the direction of the second suturesegment, the tension in the first suture segment is increased relativeto the second suture segment and, thus, the suture anchor is urged backto its original position.

In one embodiment of the present invention, the guiding arrangementincludes a suture guide which supports the first and second suturesegments, respectively, at least at a first and a second support pointswhich are laterally spaced with respect to a direction of installationof the suture anchor. Thus, at the suture guide, the first and secondsuture segments are separated laterally by a predetermined distance. Anon-parallel configuration of the suture segments near the installationend is obtained by guiding the suture segments closer togetherdownstream of the suture guide.

In another embodiment of the present invention, the guiding arrangementincludes a first and a second, longitudinally spaced, suture guideshaving a predetermined gap therebetween. The first suture guide supportsthe first and second suture segments, respectively, at least at a firstand second support points which are laterally spaced with respect to thedirection of installation of the suture anchor. The second suture guidesupports the first and second suture segments, respectively, at least ata third and a fourth support points which are laterally spaced withrespect to the direction of installation of the suture anchor. Anon-parallel configuration of the suture segments is obtained bycrossing the suture segments at a region between the first and secondsuture guides, such that the paths of the first and second suture guidesare inverted. To position the suture segments in such a crossedconfiguration, the suture segments can be simply inserted through thegap between the first and second suture guides. This obviates the needfor difficult and precision-demanding procedures for positioning thesuture, such as threading through eyes or the like, which are utilizedin prior art devices.

The installation tool of the present invention may be provided with aposition guide which ensures correct positioning of the suture anchor onthe installation end. The position guide may include a protrusion on theinstallation end adapted to fit into a notch on the suture anchor, orvice versa.

The suture anchor of the present invention may be formed with aperipheral, longitudinal groove which extends along two opposite sidesof the suture anchor. A middle portion of the suture is placed in theperipheral groove such that it does not protrude from the surface of thesuture anchor, thereby avoiding damage to the suture duringinstallation. The remainder of the suture forms the first and secondfree-ended suture segments, which extend from the suture anchor. Thus,the first and second suture segments are separated by a distancesubstantially equal to the thickness of the suture anchor. This distancecan then be changed by the suture guiding arrangement, as describedabove, to provide the non-parallel configuration.

The installation tool of the present invention may include twolongitudinal grooves which extend along opposite sides thereof Thesegrooves are used for guiding the first and second suture segments,separately, downstream of the guiding arrangement to the other end ofthe installation tool, where the suture segments can be tensioned totighten the mounting of the suture anchor and/or to compensate forlateral forces as described above. After being appropriately tensioned,the suture segments may be fixed to the installation tool.

In the present invention, the suture is utilized to firmly attach thesuture anchor to the installation end of the installation tool. Further,the suture is utilized to counteract lateral forces which may act on thesuture anchor and/or the installation end during installation. Suchlateral forces are particularly apparent when a screw-in, e.g.,threaded, type suture anchor is used. Since the suture anchor of thepresent invention is firmly mounted on the installation tool, it is easyto screw the suture anchor into a pre-drilled hole in the bone in anorthopedic procedure. The guiding arrangement firmly supports the suturesegments in the non-parallel configuration during installation. Thepresent invention is suitable for any type of suture anchor known in theart, for example, a threaded, screw-in type suture anchor or a barbed,press-in type suture anchor, as are known in the art. Further, thepresent invention is suitable for installing biostable suture anchors,for example, titanium suture anchors, as well as bioabsorbable sutureanchors, for example, reinforced polymeric bioabsorbable suture anchors,as are known in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully fromthe following detailed description of preferred embodiments of theinvention taken in conjunction with the accompanying drawings of which:

FIG. 1A is a perspective view illustration of a suture anchoroperatively mounted on an installation end of an installation tool inaccordance with an embodiment of the present invention;

FIG. 1B is a perspective view illustration of a portion of a sutureanchor and a portion of an installation tool in accordance with anembodiment of the present invention;

FIG. 2A is a schematic, front view, illustration of the suture anchorand installation tool of FIG. 1A;

FIG. 2B is a schematic, side view, illustration of the suture anchor andinstallation tool of FIG. 1A;

FIG. 2C is a partial, cross-sectional, illustration of part of theinstallation tool of FIG. 1A;

FIG. 3A is a schematic, front view, illustration of the installationtool and suture anchor of FIG. 1A, showing the full length of theinstallation tool;

FIG. 3B is a schematic, side view, illustration of the installation tooland suture anchor of FIG. 1A, showing the full length of theinstallation tool; and

FIG. 4 is a perspective view, partly cut-away, illustration of a sutureanchor operatively mounted on an installation end of an installationtool in accordance with another embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Reference is made to FIGS. 1A, 1B, 2A, 2B and 2C. FIG. 1A schematicallyillustrates a suture anchor 2 and a suture 7 operatively mounted on aninstallation tool 1 having an installation end 1a, in accordance with anembodiment of the present invention. FIGS. 2A and 2B schematicallyillustrate a front view and a side view, respectively, of installationsuture anchor 2 mounted on installation end 1a of tool 1a. Suture 7 ismounted in a peripheral groove 8 which extends along two opposite sidesof suture anchor 2, as described below. Suture anchor 2 has a drivingend 2a including a shaft 6 to which mechanical power, e.g., rotationalpower, is applied for driving the suture anchor into a bone. In theembodiment of FIG. 1A, suture anchor 2 has a threading 2b for screwingthe suture anchor into a pre-made hole, e.g., a pre-drilled hole, in thebone.

FIG. 2C illustrates a cross section of installation end 1a ofinstallation tool 1. Installation end 1a includes a cavity 4 havinginner walls, 4a and 4b, which operatively engages shaft 6 of driving end2a. Inner walls 4a and 4b of cavity 4 are preferably substantiallyplanar and parallel. The thickness of shaft 6 is preferablysubstantially equal to the distance, d, between inner walls 4a and 4b,thereby to minimize the freedom of movement of shaft 6 when seated incavity 4.

FIG. 1B schematically illustrates installation end 1a of tool 1 anddriving end 2a of suture 2 in a dismounted configuration. According toan embodiment of the present invention, cavity 4 is formed with aprotrusion 3 which may be located on either of inner walls 4a or 4b.Protrusion 3 is adapted to fit into a notch 5 formed on shaft 6 whenshaft 6 is seated in cavity 4. Thus, protrusion 3 and notch 5 areoperative to ensure correct positioning of suture anchor 2 oninstallation end 1a.

According to an embodiment of the present invention, suture anchor 2 isdriven into the bone by rotating installation tool 1. The rotation ofinstallation tool 1 is transmitted by cavity 4 of installation end 1a toshaft 6 of driving end 2a. When rotated, suture anchor 2 advances in thepre-drilled hole by virtue of threading 2b, as is known in the art.

It should be appreciated by a person of ordinary skill in the art thatthe arrangement of protrusion 3 and notch 5 can be replaced by any othersuitable arrangement for securely positioning suture anchor 2 oninstallation tool 1. Further, more than one protrusion 3 and notch 5 canbe used or the protrusion and notch can be combined with otherpositioning arrangements.

It should be further appreciated that cavity 4 and shaft 6 can bereplaced by any other suitable arrangements for transmitting therotation of tool 1 to suture anchor 2. However, for optimal driving ofsuture anchor, it is generally preferred that cavity 4 and shaft 6 havecomplementary shapes. For example, a quadrangular or hexagonal cavityand a complementary shaft can be used for cavity 4 and shaft 6,respectively.

In accordance with an embodiment of the present invention, suture 7 hastwo free ended segments, 7a and 7b, which are guided along suture anchor2 and installation tool 1, as described below, after suture anchor 2 ispositioned on installation end 1a. According to this embodiment of theinvention, suture segments 7a and 7b are guided along the two oppositesides of peripheral groove 8 of suture anchor 2. Groove 8 preventssuture 7 from protruding the surface of suture anchor 2 and, thus,protects suture 7 from being damaged during the installation of sutureanchor 2 in the bone. Suture anchors having peripheral guiding groovessimilar to groove 8 are described in Finnish Patent application No.965111, filed Dec. 19, 1996, assigned to the assignee of the presentapplication, the disclosure of which is incorporated herein byreference.

In accordance with an embodiment of the present invention, installationend la of installation tool 1 is formed with first and second sutureguides, 9a and 9b, for guiding and supporting suture 7 as describedbelow. As shown in FIGS. 1A and 2, suture segments 7a and 7b are guidedalong two opposite sides of suture guide 9a, then crossed at a region9d, between guides 9a and 9b, and finally guided along opposite sides ofsuture guide 9b. As shown in FIG. 2, suture segment 7a is supported atpoints S1 and S3 and suture segment 7b is supported at points S2 and S4.Suture segments 7a and 7b preferably extend beyond suture guide 9b andmay be further guided along grooves 8a and 8b, respectively, formed onopposite sides of installation tool 1. Thus, in this embodiment of theinvention, the paths of suture segments 7a and 7b are inverted after thesuture segments are crossed at region 9d. It should be appreciated,however, that other configurations of suture segments 7a and 7b are alsowithin the scope of the present invention. For example, if only firstsuture guide 9a is used, suture segments 7a and 7b are separately guidedat points S1 and S2 but can be guided along a single channel downstreamof points S1 and S2.

When suture segments 7a and 7b are tensioned, the tension in suturesegment 7a applies a force F1 at point S1 in the direction of point S3,and the tension in suture segment 7b applies a force F2 at point S2 inthe direction of point S4. Forces F1 and F2 are non-parallel and theangle between these forces can be controlled, e.g., by controlling thedistance between suture guides 9a and 9b and/or the width of either orboth of the suture guides. The direction of force F1 depends on therelative locations of points S1 and S3 and the direction of force F2depends on the relative locations of points S2 and S4.

In the vicinity of suture guide 9a, forces F1 and F2 have a combinedlongitudinal component, F4, and a combined lateral component, F3.Longitudinal component F4 pulls suture anchor 2 towards installation end1a and, thus, suture anchor 2 is firmly attached to installation tool 1.Since forces F1 and F2 have opposite lateral effects, the relativemagnitudes of forces F1 and F2 control the direction and magnitude oflateral component F3. Thus, force F3 can be utilized to compensate forundesired lateral forces which act on installation end 1a duringinstallation of suture anchor 2. Such compensation is not possible inprior art devices, wherein the suture segments are guided substantiallyin parallel at the installation end and, thus, have no lateral effect.

In an embodiment of the present invention, suture segments 7a and 7b arepretensioned to a predetermined, constant, tension. In this embodimentof the invention, compensation for lateral forces occurs automaticallyas follows. When suture anchor 2 is tilted in the direction of suturesegment 7a, the tension in suture segment 7b is increased and thetension in suture segment 7a is decreased and, thus, suture anchor 2 isurged back to its original position. Similarly, when suture anchor 3 istilted in the direction of suture segment 7b, the tension in suturesegment 7a is increased and the tension in suture segment 7b isdecreased and, again, suture anchor 2 is urged back to its originalposition.

Thus, it is a feature of the present invention that a guidingarrangement, such as suture guides 9a and 9b, is positioned atinstallation end la near suture anchor 2. To provide optimal control ofthe lateral forces at the installation site., support points S1 and S2are preferably as close as possible to suture anchor 2. In someembodiments of the present invention, the distance between suture guides9a and 9b and suture anchor 2 is smaller than or equal to the length ofsuture anchor 2.

Suture 7 can be conveniently mounted on installation end 1a by crossingsegments 7a and 7b and pressing them towards region 9d through a gap 9cbetween suture guides 9a and 9b. The width of gap 9c is preferably equalto or only slightly larger than the thickness of suture 7, wherebysegments 7a and 7b are conveniently inserted to region 9d and areconveniently removed therefrom, yet the suture segments cannot slip offregion 9d unintentionally. This obviates the need for difficulttechniques for threading suture which are required in prior artinstallation tools. Thus, the use of suture guides 9a and 9b and gap 9callows efficient and convenient mounting and dismounting of sutureanchor 2 and suture 7 on installation end 1a.

Reference is now made to FIGS. 3A and 3B which schematically illustratea front view and a side view, respectively, of installation tool 1 withsuture anchor 2 and suture 7 mounted thereon. As shown in FIGS. 3A and3B, suture segments 7a and 7b, which are guided along grooves 8a and 8b,respectively, extend beyond installation end 1a to a handle portion 1bof installation tool 1, where the suture segments can be convenientlyattached to installation tool 1 by wrapping them around a support member10. Suture segments 7a and 7b are preferably tensioned as they arewrapped around support member 10 until they are securely supported bythe support member. Thus, a substantially constant tension is maintainedin suture segments 7a and 7b, during installation, to ensure the firmmounting of suture anchor 2 on installation tool 1. It should beappreciated that support member 10 can be replaced by any other suitablearrangement for tensioning and supporting suture segments 7a and 7b. Forexample, each of suture segments 7a and 7b may be supported by aseparate tensioning/support arrangement, such that the tensions insegments 7a and 7b may be separately controlled.

Reference is now made to FIG. 4 which schematically illustrates a sutureanchor 12 and a suture 17 operatively mounted on an installation end 11aof an installation tool 11, in accordance with another embodiment of thepresent invention. Suture 17 is mounted in a peripheral groove 18 whichextends along two opposite sides of suture anchor 12, as described abovewith reference to suture 7 of FIG. 1A. Suture anchor 12 has a drivingend 12a and includes a plurality of barbs or scales 12b, as are known inthe art, which prevent the suture anchor from being released afterinstallation. Thus, suture anchor 12 is adapted to be installed bypressing it into a pre-drilled hole in a bone. Accordingly, in contrastto the embodiment of FIG. 1A, installation tool 11 is not provided withmeans for transmitting rotational power to suture anchor 12. In theembodiment of FIG. 4, suture anchor 12 is driven into the bone by alinear force applied by a surface 14 of installation end 11a.

According to an embodiment of the present invention, installation end11a includes a mounting/positioning rod 13 which extends from surface14. Rod 13 is adapted to be tightly fitted in a cavity 15 formed indriving end 12a of suture anchor 12. Thus, suture anchor 12 is mountedon installation end 11a simply by inserting rod 13 into cavity 15, as isknown in the art. The tight fit between protrusion 13 and cavity 15ensures correct positioning of suture anchor 12 on installation 11a.

It should be appreciated by a person of ordinary skill in the art thatthe arrangement of rod 13 and cavity 15 can be replaced by any othersuitable arrangement for securely positioning suture anchor 12 oninstallation tool 11.

Except as described above, installation tool 11 of FIG. 4 issubstantially similar to installation tool 1 of FIG. 1A, whereby similarelements of installation tool 1 and installation tool 11 are denoted bythe same reference numerals. Further, the mounting of suture 17 oninstallation tool 11, using suture guides 9a and 9b, is substantiallythe same as described above with reference to installation tool 1 ofFIG. 1A.

It should be appreciated that the present invention is not limited tothe threaded and barbed or scaled suture anchors described above and maybe used in conjunction with any other type of suture anchor. Further,the present invention can be applied to biostable suture anchors, forexample, titanium suture anchors, as well as to bioabsorbable sutureanchors, for example, reinforced polymeric bioabsorbable suture anchors,as are known in the art.

It should be appreciated by a person of ordinary skill in the art thatthe present invention is not limited to the particular embodiments thusfar described but, rather, the present invention is defined only by thefollowing claims.

We claim:
 1. A tool for installing a suture anchor which supports firstand second suture segments having free ends, the tool comprising:aninstallation end adapted to accommodate the suture anchor; and a guidingarrangement adapted to guide and support the first and second suturesegments at a crossing region, said guiding arrangement includes sutureguides for the first and second suture segments to cross at theinstallation end.
 2. The tool according to claim 1 wherein a firstsuture guide is adapted to support the first and second suture segments,respectively, at least at a first and a second support points, which arespaced laterally with respect to a direction of installation of saidsuture anchor.
 3. The tool according to claim 2 wherein said guidingarrangement comprises first and second suture guides which are spacedalong said installation axis, wherein the first suture guide is adaptedto support the first and second suture segments, respectively, at leastat said first and second support points, and wherein the second sutureguide is adapted to support the first and second suture segments,respectively, at least at a third and fourth support points, which arespaced laterally with respect to said direction of installation.
 4. Thetool according to claim 3 wherein said first and second suture guidesare separated by a gap through which the first and second suturesegments are introduced to said crossing region.
 5. The tool accordingto claim 4 wherein the width of said gap is equal to the thickness ofsaid suture segments.
 6. The tool according to claim 1 wherein thedistance between the guiding arrangement and the suture anchor is lessthan the length of the suture anchor.
 7. The tool according to claim 2wherein the distance between the guiding arrangement and the sutureanchor is less than the length of the suture anchor.
 8. The toolaccording to claim 3 wherein the distance between the guidingarrangement and the suture anchor is less than the length of the sutureanchor.
 9. The tool according to claim 8 wherein the distance betweenthe suture anchor and said crossing region is less than the length ofthe suture anchor.
 10. The tool according to claim 4 wherein thedistance between the suture anchor and said crossing region is less thanthe length of the suture anchor.
 11. The tool according to claim 5wherein the distance between the suture anchor and said crossing regionis less than the length of the suture anchor.
 12. The tool according toclaim 1 comprising a tensioning arrangement which supports the free endsof the first and second suture segments, wherein a substantiallyconstant tension is maintained in each of the suture segments betweenthe tensioning arrangement and said guiding arrangement.
 13. The toolaccording to claim 2 comprising a tensioning arrangement which supportsthe free ends of the first and second suture segments, wherein asubstantially constant tension is maintained in each of the suturesegments between the tensioning arrangement and said first suture guide.14. The tool according to claim 3 comprising a tensioning arrangementwhich supports the free ends of the first and second suture segments,wherein a substantially constant tension is maintained in each of thesuture segments between the tensioning arrangement and said first sutureguide.
 15. The tool according to claim 4 comprising a tensioningarrangement which supports the free ends of the first and second suturesegments, wherein a substantially constant tension is maintained in eachof the suture segments between the tensioning arrangement and said firstsuture guide.
 16. The tool according to claim 5 comprising a tensioningarrangement which supports the free ends of the first and second suturesegments, wherein a substantially constant tension is maintained in eachof the suture segments between the tensioning arrangement and said firstsuture guide.
 17. The tool according to claim 6 comprising a tensioningarrangement which supports the free ends of the first and second suturesegments, wherein a substantially constant tension is maintained in eachof the suture segments between the tensioning arrangement and saidguiding arrangement.
 18. The tool according to claim 7 comprising atensioning arrangement which supports the free ends of the first andsecond suture segments, wherein a substantially constant tension ismaintained in each of the suture segments between the tensioningarrangement and said first suture guide.
 19. The tool according to claim4 wherein the width of said gap is larger than the thickness of saidsuture segments.
 20. The tool according to claim 1 wherein the distancebetween the guiding arrangement and the suture anchor is equal to thelength of the suture.
 21. The tool according to claim 2 wherein thedistance between the guiding arrangement and the suture anchor is equalto the length of the suture anchor.
 22. The tool according to claim 3wherein the distance between the guiding arrangement and the sutureanchor is equal to the length of the suture.
 23. The tool according toclaim 3 wherein the distance between the suture anchor and said crossingregion is equal to the length of the suture anchor.
 24. The toolaccording to claim 4 wherein the distance between the suture anchor andsaid crossing region is equal to the length of the suture anchor. 25.The tool according to claim 24 wherein the distance between the sutureanchor and said crossing region is equal to the length of the sutureanchor.
 26. Th etool according to claim 1, wherein the installation endis adapted to transmit mechanical power for driving the suture anchorupon installation of the anchor into bone.